Conventionally, as this type of cylinder device, for example, a cylinder device that is used by being interposed between a vehicle body and a carriage of a railway vehicle for suppressing oscillation in the left-right direction relative to the traveling direction of the vehicle body is known.
Such a cylinder device is configured to include, for example, a cylinder; a piston that is slidably inserted into the cylinder; a rod that is inserted into the cylinder and connected to the piston; a rod-side chamber and a piston-side chamber that are partitioned by the piston within the cylinder; a tank; a first opening and closing valve that is provided in a first passage and allows the rod-side chamber to communicate with the piston-side chamber; a second opening and closing valve that is provided in a second passage and allows the piston-side chamber to communicate with the tank; a pump that supplies a liquid to the rod-side chamber; a motor that drives the pump; a discharge passage that connects the rod-side chamber to the tank; and a variable relief valve provided in the discharge passage (for example, refer to JP 2013-1305A).
According to this cylinder device, the first opening and closing valve and the second opening and closing valve are appropriately opened and closed to determine a direction of a thrust to be output, and the pump is rotated by the motor at a constant speed to supply a fixed flow amount to the inside of the cylinder while adjusting the relief pressure of the variable relief valve, thereby controlling the pressure within the cylinder. Thus, a thrust of a desired magnitude can be output in a desired direction.
Further, another cylinder device is configured to include, for example, a cylinder; a piston that is slidably inserted into the cylinder; a rod that is inserted into the cylinder and connected to the piston; a rod-side chamber and a piston-side chamber that are partitioned by the piston within the cylinder; a tank; a first opening and closing valve that is provided in a first passage and allows the rod-side chamber to communicate with the piston-side chamber; a second opening and closing valve that is provided in a second passage and allows the piston-side chamber to communicate with the tank; a discharge passage that connects the rod-side chamber to the tank; and a variable relief valve provided in the discharge passage (for example, refer to JP 2000-238637A).
According to this cylinder device, the first opening and closing valve and the second opening and closing valve are appropriately opened and closed to determine a direction of a damping force to be output, and the relief pressure of the variable relief valve is adjusted to control the pressure within the cylinder. Thus, a damping force of a desired magnitude can be output.
On the other hand, in a railway vehicle in which such a cylinder device is utilized, when the vehicle body moves in the left-right direction relative to the carriage, if the movement of the vehicle body is permitted without restriction, the railway vehicle may contact oncoming vehicle, or the railway vehicle may contact a tunnel inner wall while traveling through a tunnel. Therefore, movement limits in the left-right direction of the vehicle body are established.
Specifically, a center pin is provided on the bottom of the vehicle body, and on the carriage side, a pair of stoppers are provided at spaced apart positions on the left and right sides of the center pin. When the vehicle body moves in the left-right direction relative to the carriage, the center pin will collide with the stoppers if the movement limit is reached, and thus the movement of the vehicle body relative to the carriage is restricted.